Typically, electrical power supplied for residential applications is single phase alternating current power. To measure the consumption of electricity in residential applications, a utility company meter is provided at the electrical service entrance to the residence. Utility company meters are of three general types, namely, electromechanical based meters, purely electronic component based meters, and hybrid electromechanical/electronic meters. The electromechanical and hybrid type meters are essentially an induction motor in which the moving element is a rotating disk. The speed of rotation of the disk is directly proportional to the voltage applied and the amount of current flowing through the motor. The phase displacement of the current, as well as the magnitude of the current, is automatically taken into account by the meter, i.e., the power factor influences the speed of rotation of the disk. The result is that the disk rotates with a speed proportional to true power. In the electromechanical type of meters, a register is used to register the number of revolutions, and the gearing is arranged to be read directly in kilowatt-hours.
The electric utility meters most commonly in use are of the electromechanical type. The meters are generally highly reliable, but do not lend themselves to remote or automated reading.
Hybrid meters typically utilize electronic circuitry in combination with the rotating disk to permit at least limited two-way communication to/from the meter. Typically, the two-way communication is limited to reading the meter via a proprietary communications link that frequently is a limited range radio frequency link.
It is not uncommon for electric utilities to utilize both simple and complex tariffs. The tariffs may be time of use type tariffs, or may be changed from time to time or on predetermined dates to provide for various time of use type of rates.
It is common practice for utility companies to access meter information on only a monthly or 30 day period.
In addition, present metering technology makes it inconvenient for a consumer to determine in a timely fashion the amount of energy being consumed.
One problem with electronic programmable automatic metering systems is the difficulty of reprogramming meters that are in the system.